1. Field
Some preferred embodiments of the present invention relate to an audio signal processing apparatus that performs various processes to an audio signal.
2. Description of the Related Art
Conventionally, sound field supporting devices that form a desired sound field in a listening environment have been known (see JP 2001-186599 A, for example). The sound field supporting devices generate a pseudo reflected sound (sound field effect sound) by combining audio signals of a plurality of channels and convolving a predetermined parameter to the combined audio signals.
On the other hand, in recent years, a sound image localization method by object information imparted to content has been widely used. The object information includes information indicating a position of an object. The object is a term corresponding to a “sound source” in the sound image localization method using object information.
Sound field effects, however, have not been optimized for the sound image localization method by the object information. For example, since the sound field effects are preferably reduced in a case in which the type of the sound source is a sound such as speech, a front signal or a surround signal that is likely to contain a great number of components such as music has a high contribution rate while a center signal that is likely to contain a great number of components such as speech has a low contribution rate.
In such a state, in a case in which an object moves from the front to the back, for example, as a sound image localization position of the object changes from the front to the back, the sound field effects may be drastically increased in some cases.
Moreover, in the sound image localization method by the object information, the audio signals that have been channel distributed based on the listening environment (speaker arrangement mode) are only input and the position information itself of the original object may not be obtained in other cases.
Furthermore, in a case in which content is recorded in a small concert hall, for example, and the sound field effect of a large concert hall as the listening environment is set to be imparted to the content, an indirect sound is spread while the position of a direct sound (each sound source) is not changed.
In view of the foregoing, some preferred embodiments of the present invention are directed to provide an audio signal processing apparatus that forms an optimum sound field for each object.
In addition, other preferred embodiments of the present invention are directed to provide an audio signal processing apparatus that estimates position information of an object contained in content.
Moreover, some other preferred embodiments of the present invention are directed to provide an audio signal processing apparatus that imparts a proper sound image position.